Refrigerant reversal valves



June 29, 1965 w. L. GOURTNEY 3,191,527

REFRIGERAN'I REVERSAL VALVES Filed May 24,, 1963 40 7 1 SOLENOID REFRIGERANT COMPRESSOR REVERSAL VALVE i llllllllll H :1 E

/6 e/ a3 INDOOR AIR COIL OUTDOOR AIR con.

E I /3 6'0 '2. 86 as United States Patent 3,191,627 REFRIGERANT *REVERSAL VALVES Watson L. 'Courtney, Staunton, Va., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed May 24, 1963, Ser. No. 283,049 1 Claim. (Cl. 137 62529) This invention relates to heat pumps that are used for cooling or heating indoor air, and relates more particularly to reversal valves for such heat pumps.

A heat pump used for cooling or heating indoor air usually includes a refrigerant compressor that is connected through a refrigerant reversal valve to indoor heat exchange and to outdoor heat exchange coils. When indoor air heating is required, the reversal valve is ad- Patented June 29, 1965 through its compressor into the low pressure coil of the Y heat pump when the reversal of the valve of the latter is shown in an intermediate position where it opens a byjusted to one position to route refrigerant from the compressor through the indoor coil operating as a condenser, and thenthrough refrigerant expansion means into the outdoor coil operating as an evaporator. 'When indoor air cooling is required, the reversal valve is adjusted to its other position to route refrigerant from the compressor through the outdoor coil operating as a condenser, and through refrigerant expansion means into the indoor coil operating as an evaporator.

When the reversal valve of such a heat pump is adjllStfidWhllC itsassociated refrigerant compressor is still operating or has been stopped for a short period of time,

at the instant of reversal, the compressorsuction is applied to the high pressure coil that has been operating as a condenser, and the high pressure refrigerant from the latter discharges through the compressor into the low pressure coil that has been operating as an evaporator. This creates undesired noise, often damages the compressor valves, and refrigerant liquid from the high pressure coil passes into the compressor, diluting its lubricant, and causing increased wear of components.

In a widely used heat pump, a heat thermostat when it calls for indoor air heat, energizes a solenoid which adjusts the reversal valve of the heat pump to its air heating position. When the heat thermostat is satisfied, it deenergizes the solenoid which then adjusts the reversal valve to its air cooling position. The heat thermostat cycles the compressor during air heating operation. A cool thermostat cycles the compressor during air cooling operation.

When such a heat pump is operating to heat indoor air with its outdoor coil operating as an evaporator, low outdoor temperatures may cause frost to form on the outdoor coil, and to melt such frost, it has been the practice to use a pressurestat responsive to air pressure drop through the outdoor coil caused by the frost, to adjust the reversal valve to its indoor air cooling position so as to operate the outdoor coil as a condenser. Then, when the frost has melted, a control responsive to the rise in refrigerant pressure within the outdoor coil caused by the melting of the frost, adjusts the reversal valve back to its indoor air heating position.

Thus, in such a heat pump, a refrigerant reversal valve is adjusted to reverse the flow of refrigerant each time the heat thermostat cycles, and when defrosting of the outdoor coil is started and stopped.

This invention prevents the refrigerant from the high pressure coil from flowing through the compressor into the low pressure coil when the reversal valve is adjusted by providing a by-pass passage within a reversal valve which' is opened to connect the high and low pressure coils together for a sufficient period of time while the valve is being adjusted, for the pressures to equalize.

An object of this invention is to prevent refrigerant from a high pressure coil of a heat pump from flowing pass passage, and

FIG. 3 is a side section of the valve with its piston shown in its air cooling position. i

A refrigerant compressor 10 has its discharge side connected by a tube 11 to a gas inlet port 12 of a refrigerant reversal valve 13. The suction side of the compressor 10 is connected by a tube 14 to a gas outlet port 15 of the valve 13, the ports 12 and 15 being opposite each other. The valve 13 has a port 16 to one side of the I port 12, connected by a tube 17 to an indoor air coil 18,

and has a port 19 to the other side of the port 12, connected by a tube 20 to outdoor air coil 21. The coils 18 and 21 are connected by a capillary tube 23 which serves as a two-Way refrigerant expansion means.

The valve 13 contains a piston 25 which has a circular passage 26 extending therethrough and which is positioned to line up with the ports 15 and 19 when the piston 25' is adjusted to its air heating position as shown by FIG. 1. The piston 25 has a cavity 28 in its surface opposite the ports 16, 12 and 19, and which, when the piston is in its air heating position, connects the port 12 with the port 16. Thus, when the piston 25 is in its air heating position as shown by FIG. 1, the flow of refrigerant is from the discharge side of the compressor 10, through the tube 11, port 12, cavity 28, port 16, tube 17, indoor coil 18, capillary tube 23, outdoor coil 21, tube 20, port 19, passage 26, and tube 14 to the suction side of the compressor 10. The indoor coil 18 operates a condenser coil to heat the indoor air.

The piston 25 has a circular passage 30 extending therethrough and which is positioned to line up with the ports 15 and 16 when the piston is adjusted to its air cooling position as shown by FIG. 3. At this time, the cavity 28 connects the port 12 to the port 19. At this time, the flow of refrigerant is reversed, the discharge gas from the compressor 10 supplied through the port 12, flowing through the cavity 28, the port 19 and the tube 20 to the outdoor coil 21 which is operating as a condenser coil, and flowing from the indoor coil 18 which is operating as an evaporator coil, through the port 16, passage 30 and port 15 to the suction side of the compressor.

When the piston 25 is moving from its air heating position to its air cooling position and vice versa, at an intermediate position shown by FIG. 2, the cavity 28 connects the ports 16, 12 and 19. Assuming that the piston 25 has just moved from its air cooling position shown by FIG. 3, to the intermediate position shown by FIG. 2, the high pressure refrigerant from the coil 21 which has been operating as a condenser, flows through the tube 2!), port 19, cavity 28, port 16 and tube 17 into the coil 18 which has been operating as an evaporator.

When the piston 25 is moved from its air heating position shown by FIG. 1 to the intermediate position shown by FIG. 2, the refrigerant flow is from the indoor coil 18 which has been operating as a condenser coil, through the tube 17, port 16, cavity 28, port 19 and tube 20 to the outdoor coil 21 which has been operating as an evaporator coil.

Thus, each time the piston 25 is adjusted to reverse the For adjusting the piston 25, the ends of the valve 13 are connected through orifices 36 of fittings 37 and conventional pilot tubes 38 to a conventional three-Way pilot valve 40. A conventional small tube 41 connects the valve 40 to the discharge gas tube 11 as is conventional. A conventional solenoid 44 operates the valve 4% in a conventional manner to admit discharge gas into one or the other of the two pilot tubes 38 for supplying the high pressure gas against one end or the other end of the piston 25 for moving the latter from its air heating position to its air cooling position, and vice versa. Usually, when the solenoid 44 is deenergized, it operatesthe' valve 40 to supply discharge gas against the left end of the piston 25 for moving it to its air cooling position, and when the solenoid 44 is energized, it operates the valve 40 to supply discharge gas against the right end of the piston 25 for moving it to its air heating position. The fittings 37 are conventional except that they are provided with the orifices 36 which additionally constrict the gas passagesconnected to the ends of the reversal valve 13 for slowing down the movement of the piston 25 so that its cavity 28 can connect the ports 16 and 19 together for a period of time sufficient for the pressures in the high and low pressure coils to equalize.

The reversal valve 13, its pilot valve 40 and its solenoid 44 are similar to those in a conventional Ranco reversal valve system as describedin the Ranco Service Manual No. 1058, except for the locations of the suction and discharge gas ports being reversed, except'for the different piston design, and except for the provision of 4 the orifices 36, in the gas fittings in the ends of the reversal valve.

What is claimed is: V r

A refrigerant reversal valve having a central discharge gas port in one side for connection to the discharge side of a refrigerant compressor, having a second port to one side of said port for connection to a heat exchange 1 coil, having a third port in said one side of said valve to the opposite side of said discharge gas port for connection to another heat exchange coil, and having a suction gas port in the opposite side of said valve opposite said discharge gas port for connection to the suc tion side of said compressor, a piston slidable within said valve from one end of said valve to the opposite endvof said valve, said piston when at said one end of said valve having a passage connecting said third and suction gas ports and having a'cavity connecting said discharge gas and secondports and extendingtowards said one end substantially beyond said second port, said piston when at said opposite end of said valve having a passage connecting said second and suction gas ports with said cavity connecting said discharge gas and third 7 ports and extending towards said opposite end substantially beyond said third port, said cavity when said piston is at an intermediate position between said ends connecting said discharge gas, said second and said third ports;

References Cited by the Examiner UNITED STATES PATENTS 2,867,237 1/59 Allingham l37625.43 XR 2,983,286 5/61 Greenawalt 137-62543 3,055,394 9/62 Dilliner 25131 XR 3,056,574 10/62 Grcenawalt 137625.29 XR M. CARY NELSON, Primary Examiner. 

